With a word processor or other desktop publishing application, a user can open or create an electronic document. To print, the application, with use of an operating system, sends instructions to a print driver to assemble a print job for a laser printer or other image forming device. The print driver acts as a translator between the application and the image forming device, transforming generic printing instructions received from the application into device specific instructions—print jobs—capable of being acted upon by the image forming device.
An electronic document can be made of up of text, line-art, and/or raster data. Text and line art, as compared to raster data, require relatively small amounts of memory. Raster data are pixels selected and arrange to reveal one or more images. For black and white images, each pixel can be represented by a single bit. A high quality, color image can require forty bits to define each pixel. A relatively small 800×600 pixel high quality, color image, then, can be 19,200,000 bits or 2.4.megabytes in size.
Once the print job is assembled, the print driver transmits the print job through a physical computer port to the image forming device. Port examples include wired or wireless Ethernet, USB (Universal Serial Bus), parallel, serial, and infra-red ports. Different ports have different transmit rates. For example a print job sent through an Ethernet port will be delivered more quickly than a print job sent through a serial port. Smaller print jobs are transmitted relatively quickly regardless of the type of port used. However, a larger print job—for example, a job containing a large amount of raster data—can require a noticeable amount of time to be transmitted resulting in a significant delay when transmitted through a slower port.